There are many different antiperspirant formulations known for controlling or inhibiting underarm perspiration and odor. Most of the currently marketed formulations comprise an antiperspirant powder such as an aluminum salt, which is suspended in an anhydrous carrier. Suspension of the active is typically achieved by controlling the viscosity of the anhydrous carrier such that the active is homogenously distributed throughout the product during product dispensing. This viscosity increase can be very high for solid products (more than 3 million centipoises (cps)), high for cream products (25,000 to several million cps) and fairly low for liquid products such as aerosols and roll-ons (300 to 5,000 cps).
One formulation method that can be used to remove the need to suspend the particulate active is to dissolve the active in a carrier liquid. Although any product form can be created using an active dissolved in a carrier liquid, they are most commonly formulated as liquids and delivered as sprays, roll-ons, and water or polar solvent in silicone emulsions. This method removes the need to suspend the active; however many formulations still require control of product viscosity to allow the product to be dispensed in a convenient manner. There are many examples of products based on solubilized active where the carrier liquid comprises a high level of water (more than 20%) that acts as the solvent for the aluminum salt antiperspirant active. Generally, these products are sold as emulsions, either oil in water or water in oil and range in viscosity from about 100 cps for a roll-on to 100,000 cps for water-in-silicone emulsion gel product. The required viscosity of the product is typically dependent on the type of package that is used to deliver the product but can also be driven by need the prevent phase separation of the emulsion. Anhydrous products based on solubilized actives are less common in the market place but there are several examples disclosed in the prior art. U.S. Pat. No. 5,814,309 (Sep. 29, 1998, Panitch) discloses a transparent aerosol composition comprising an active antiperspirant salt, a carrier, and a hydrocarbon gas propellant.
Low-viscosity (less than 100 cps) anhydrous liquid products can be formulated as sprays but as such are prohibited from using high efficacy aluminum and zirconium based antiperspirant actives in many markets due concerns over the inhalation. Roll-on products can use aluminum and zirconium actives and can be formulated to have a wide variety of viscosities; however, the roll-on products lack the ability to control product dose independently of spreading the product, i.e., the roll-on product continues to dose as long as the package is being rubbed on the skin. Anhydrous emulsions are also known in the art. U.S. Pat. No. 5,989,531 (Nov. 23, 1999, Schamper et al.) discloses liquid composition, which provides a drier feel and reduces leakage when used with certain types of applicators. However, the formulations that require a high polar solvent phase to silicone emollient phase ratio have a high viscosity—higher than 2000 centipoises—that is undesirable because it may be difficult to spread over the underarm skin.
Another way to deliver liquid products in cosmetically acceptable manner is to convert the liquid to foam prior to application. The conversion of the composition into foam causes the increase of apparent viscosity of the foam composition without increasing its true viscosity. This allows a foam product having a relatively low true viscosity but a relatively high apparent viscosity to be spread easily in the underarm area. Moreover, the gas or air entrapped in the foam is believed to create a drier feel during application.
Pressurized foam products are typically packaged in metal cans, or glass or plastic containers. These pressurized containers are typically fitted with a valve to close the package and release the pressurized product when actuated by the user. U.S. Pat. No. 2,746,796 (May 22, 1956, Germain) discloses a metering valve aerosol bottle. U.S. Pat. No. 6,494,349 (Dec. 17, 2002, Thompson, et al.) discloses a hand-held product dispenser comprising a valve mechanism for adjusted “throttled” delivery of the product. U.S. Pat. No. 3,685,913 (Aug. 22, 1972, Pass) discloses an applicator for spreading of shave cream lather, depilatories, unguents and the like substances. UK Patent Application GB 2214891A discloses a container for pressurized material. U.S. Pat. No. 5,813,785 (Sep. 29, 1998, Baudin et al.) discloses a device for packaging, dispensing and application of a product packaged in a liquid form and dispensed in the form of foam or gel. U.S. Pat. No. 5,567,073 (Oct. 22, 1996, de Laforcade) discloses an applicator device for liquid, including a container and a dispenser head connected to the container via a dispenser cap. GB 1098951 discloses a collapsible foam aerosol antiperspirant. GB 1170152 discloses foam antiperspirant products. JP 49037882 discloses foaming aerosol compositions containing alcohols, cellulose and/or vinyl-type polymers, organic solvents, and propellants. U.S. Pat. No. 5,914,085 (Jun. 22, 1999, Zimmerhackel) discloses an actuator for an aerosol container for dispensing foam.
The disclosed in the prior art dispensing actuators to convert a liquid product into foam and those that integrate an application surface into the dispensing orifice can provide an advantage for products such as carpet cleaners and shave foams in that they avoid the need for the user to touch the product with a hand during application or use a secondary application device such as a brush, a towel, or an applicator pad. Further, these packages that provide an integrated application surface can be adapted to include several types of mechanisms to actuate the valve to cause product to flow to the application surface. While these applicator designs are useful for the application of many foam products, they fail to address several important needs for an antiperspirant foam product. For example, these applicators do not address the need to prevent the foam from sliding off the applicator, they do not address the need to prevent the foam from becoming airborne as it is dispensed, and they do not address the need to rub a very thin layer of the product onto the skin.
Known foaming antiperspirant compositions are designed to be applied by hand to the underarm. Now, it has been discovered that the use of an integral applicator for a foaming antiperspirant is desirable since it avoids the need for the user to touch the product prior to application, thus being less messy and more convenient. Moreover, there are several important design elements of an integral applicator for a foaming antiperspirant that must be considered. First, it is important that the dispensed product not slide off the applicator prior to application to the underarm. Second, it is important that the product not become airborne upon dispensing so as to prevent the product being inhaled be the user, creating a mess, or possibly damaging a surrounding surface (e.g. staining, discoloring). Third, it is important that the applicator spread the product out broadly distributed on the applicator surface so as to maximize coverage during application, while at the same time ensuring the foam does not run off the sides of the applicator. The need to avoid dispensing too much product onto the application surface (commonly referred to as “overdosing”) is also important; if too much product is dispensed, the product is more prone to drip, slide, or fall off the application surface, which causes messiness.
The foaming antiperspirant products that were designed to be initially applied by dispensing the foam onto the consumer hand (like most shaving creams) and then rubbed onto the underarm skin are less desirable. This two-step process leaves some of the sticky antiperspirant active on the hand and causes overdosing of the product, both of which are undesirable side effects of the two-step process.
The present invention is directed to an antiperspirant product comprising a combination of an antiperspirant composition and an applicator therefor, having a specific set of characteristics that would allow a consumer to apply a small predetermined amount of an antiperspirant composition in a single-step process from the applicator directly to the underarm area while avoiding overdosing of the product, its sliding off the applicator and accompanying messiness, minimizing the potential for the composition to become airborne while maximizing the composition coverage area during its application to the skin.
In the case of a clear foam antiperspirant composition, it is desirable to allow the user to see the clear product. The user is better able to understand that the foam product will go on clear, since while the foam is opaque when dispensed onto the application surface, it returns to a clear fluid when rubbed against the underarm. Thus, it is desirable to package a clear antiperspirant foam product in a clear container, such as a clear plastic container.